Pressure wave actuating means for type hammers in high speed printers



' March 28, 1967 PRESSURE INVENTOR. SIEGFRIED SCHMIDT AGENT March 28, 1967 s. SCHMIDT 3, PRESSURE WAVE ACTUATING MEANS FOR TYPE IGH SPEED PR HAMMERS IN H INTERS Filed Nov. 12. 1964 2 Sheets-Sheet 2 INVENTOR SIEGFRIED SCHMIDT United States Patent 7 Claims. (in. 101-1 For data provided by, for example, electronic computers, use is made of so-called high-speed'printers. To arrive at maximum printing speeds, known mechanical high-speed printers utilize the method of flying printing. In this method the character forms (types) to be printed, which are present on a chain or a roller, are continuously moved past the stationary paper. When a given character has to be printed, a small hammer driven mechanically or electromechanically, when the desired type is just present on one side of the paper, is thrust against the paper from the other side, resulting in printing. Colour is added either by interposing coloured tape or coloured paper, or by colouring the types.

The printing operation is a shock process. Its duration is the time during which a force acts between the hammer and the type. This time must be so short that the type may he regarded as stationary during this action period. If the character form during this period moves on over a greater length a vague print results. To arrive at short action periods for a given required printing force, the mass of the hammer must be as small as possible and its speed as high as possible.

In conventional mechanical printing systems the hammer is driven by an electromagnet through a rod system or by a toothed wheel. The hammer speeds obtainable are then limited by the inertia of the rod system or by the maximum permissible peripheral speed of the toothed wheel.

When the operating speed is considerably increased the known methods of synchronisation fail, being after all entirely dependent on the operation by electromagnets, for although the period of contact between the hammer and the paper may be very short in mechanical printing systems, a comparatively long time still elapses between the starting of the operation (for example the energisation of an electromagnet) and the impact of the hammer.

Fluctuations in this operating period, which is not the same for each print, give rise to synchronisation errors. If the permissible synchronisation error, as in known mechanical high-speed printers, is considerably smaller than the operating period this implies that the fluctuations in the operating period must 'be not more than a few percent. Thus, the constancy of the operating period has to satisfy very high requirements already at the printing speeds known today.

The present invention relates to a method of printing or stamping and is characterized in that the printing or stamping operation is brought about by a pressure wave released or generated through an electric discharge.

In the method according to the invention, even if the printing speed is raised, considerable relative fluctuation in the operating period is still permissible since this operating period itself is of the order of the permissible time fluctuations.

By using a spark gap only a very short time (smaller than 1 sec.) is required for starting the printing or stamping operation. The control may be effected purely electronically so that the synchronisation does not cause difliculty even at speeds, which are considerably higher speeds than the speeds attainable with known printers.

3,311,050 Patented Mar. 28, 1967 Another advantage of the new high-speed printer is the small dimensions of the spark distance, which constitutes as-it-were the driving or control member. This renders superfluous the supply of printing or starting energy required with electromagnets and which is effected through rods which in turn counteract a high speed because of their mass and inertia moment.

The new high-speed printer is also suitable for embossing such as used, for example, in the manufacture of multiplicator matrices and Braille script. Further the transport of the material to be printed maytake place very rapidly.

In order that the invention may be readily carried into effect, a few embodiments will now be described in detail, by way of example, with reference to the accompanying diagrammatic drawings.

FIG. 1 shows a partial section of an electrical impulse actuated printing structure.

FIG. 2 shows a partial section actuated embossing structure.

FIG. 3 shows a partial section of an electrical impulse actuated printing structure utilizing a hammer surface.

FIG. 4 shows a partial section of an electrical impulse actuated printing structure utilizing a hermetically sealed hammer.

FIGURE 1 shows the principle of a device for flying printing with the aid of a gas pressure wave produced by a spark. Electrodes 1 are held by an insulator 2 and extend into a discharge space 3' which may be filled, if desired, with a gas at a pressure above atmospheric pressure. The spark is produced by, for example, the discharge of .a capacitor. The initiation of the discharge (ignition of the spark) may be obtained in different ways. In FIGURE 1, for example, an additional igniting electrode 4 is provided. In this case the electrodes 1 are directly connected to a capacitor 5 which contains the necessary energy to be released in the spark.

The discharge of the capacitor 5 through the electrodes 1 is initiated by a high-tension pulse at the igniting electrode 4. This discharge produces a gas-pressure wave by which paper sheets 6 and 7, together with interposed coloured papers 8 and 9, for example, carbon paper, are pushed against one of the character forms (types) 10. This results in the desired character being printed on the original 6. and on further carbon copy sheets only one of Which, designated 7, is shown in the example. The coloured paper 8 in front of the original may alternatively be replaced by a coloured tape or cloth. The types 10 are as reliefs arranged on a fastmoving type carrier 11, for example, a type roller as shown in section in FIGURE 1.

The device shown in FIGURE 2 is suitable for flying intaglio printing and flying embossing. The essential difference from the device of FIGURE 1 consists in that, for example, a slide spark gap 3 is used for generating the pressure waves and that types 14 are engraved in a roller 13. In this case only one sheet or one foil 12 is present. For colour printing the types 14 are filled with coloured ink. By means of the gas-pressure waves generated by the electric discharge a print is thus obtained in the manner of intaglio printing. When the energy of the discharge is increased and the types 14 exhibit an engraved form suitable therefor it is possible to emboss the fiat material 12 by the same device. By providing the types 14 with printing ink it is then alsopossible t-o blacken the embossed areas of the material 12 obtained by the embossing operation.

of an electrical impulse When the gas-pressure wave is used directly as in the devices of FIGURES 1 and 2, it is advantageous if the distance between the electrodes is made equal to the largest height of the characters to be printed.

FIGURE 3 shOWs the principle of a device in which a counter surface is used. It differs from the device of FIGURE 1 only in that a light-weight hammer 15, which serves as the counter surface, is arranged between the discharge space 3 and the paper 4 to 9. The said hammer is held, for example, by thin wire springs 16. In this case the hammer 15 is accelerated by the gas-pressure wave and pushes the paper against the type 10.

FIGURE 4 shows the principle of a device having a discharge space which is hermetically closed. In this example the discharge space 3 may be filled with a medium which is advantageous for the discharge. Thus a gas such as, for example, hydrogen is advantageous in known manner if the sparks rapidly succeed one another since the recombination time is then short. This device is particularly advantageous, however, if the discharge space is to be filled with a liquid, for example, water. This is advantageous if it is desired to exert great forces with a small stroke of the hammer.

In the said device the discharge space 3 is housed in a metallic body 17 closed on one side by a diaphragm 18. Placed on the diaphragm is a thin plate of tungsten 19 which constitutes the hammer and at the same time one electrode. The second electrode 20 passes through an insulator 21 into the discharge space 3.

What is claimed is:

1. In high speed printing apparatus the improvement comprising means defining spaced juxtaposed surfaces, the space between said surfaces not being substantially greater than the thickness of an element to be marked and which is received in said space, said means having a concavity opening into the space between said surfaces, electrode means terminating within said concavity, a

. hammer, and means mounting said hammer within said cavity having a surface bounding the said space whereby discharge of said electrode means generates a shock wave in said concavity which is shaped by said cavity and impinges on said hammer.

2. High speed printing apparatus according to claim 1 wherein said concavity is hermetically closed by a diaphragm means, said diaphragm means including said hammer and a gaseous medium having a short recombination time filling said concavity.

3. High speed printing apparatus according to claim 1 wherein said concavity is hermetically closed by a diaphragm means including said hammer, and a conducting liquid completely filling said concavity.

4. High speed printing apparatus accordingto claim 2 wherein said electrode means includes said hammer.

5. High speed printing apparatus according to claim 3 wherein said electrode means includes said hammer.

6. In high speed printing apparatus, the improvement comprising means defining juxtaposed first and second surfaces, the space between said surfaces not being substantially greater than the thickness of an element to be marked, said element to be marked being located in said space, a substantially semi-spherical cavity in said first surface which opens into the space between said surfaces, said cavity containing a fluid, electrode means terminating within said cavity in relatively remote spaced relation from the element to be marked, said second surface containing marking means, whereby discharge by said electrode means generates a shock wave in said fiuid in said cavity which is reinforced by said cavity wall and forces said element to be marked against said marking means.

7. High speed printing apparatus according to claim 6 wherein said electrode means includes an igniting electrode at the apex of said semi-spherical cavity and said electrode means are positioned away from the wall defining s-aid semi-spherical cavity.

References Cited by the Examiner UNITED STATES PATENTS 2,151,638 3/1939 Genschmer 101-4 X 2,405,714 8/1946 Ryan 1014 X 2,604,042 7/1952 Cook 101426 2,737,882 3/1956 'Early et a1 1013 3,015,263v 1/1962 Lounsberry et al. 10119 3,149,562 9/1964 Wilkins et al 101--'93 WILLIAM B. PENN, Primary Examiner. 

1. IN HIGH SPEED PRINTING APPARATUS THE IMPROVEMENT COMPRISING MEANS DEFINING SPACED JUXTAPOSED SURFACES, THE SPACE BETWEEN SAID SURFACES NOT BEING SUBSTANTIALLY GREATER THAN THE THICKNESS OF AN ELEMENT TO BE MARKED AND WHICH IS RECEIVED IN SAID SPACE, SAID MEANS HAVING A CONCAVITY OPENING INTO THE SPACE BETWEEN SAID SURFACES, ELECTRODE MEANS TERMINATING WITHIN SAID CONCAVITY, A HAMMER, AND MEANS MOUNTING SAID HAMMER WITHIN SAID CAVITY HAVING A SURFACE BOUNDING THE SAID SPACE WHEREBY DISCHARGE OF SAID ELECTRODE MEANS GENERATES A SHOCK WAVE IN SAID CONCAVITY WHICH IS SHAPED BY SAID CAVITY AND IMPINGES ON SAID HAMMER. 